Method for preparing copper-iron composite-type SAPO-34 molecular sieve catalyst

The invention relates to a method for preparing a copper-iron composite-type SAPO-34 molecular sieve catalyst, and the method comprises the following steps: stirring fully pseudoboemite in deionized water, adding phosphoric acid for complete peptization of the pseudoboemite, adding silica and a copper salt, evenly stirring, adding triethylamine and tetraethylenepentamine, stirring, and filling into a reactor after stirring for crystallization to obtain CuSAPO-34 molecular sieve; adding an iron or iron-copper salt mixture in deionized water, adding ammonia to adjust the pH value of the salt solution to 1 to 6; mixing the salt solution with the CuSAPO-34 molecular sieve for thermostatic waterbath, then washing, drying and roasting the obtained solid product to obtain the copper-iron composite-type SAPO-34 molecular sieve catalyst. The method not only greatly simplifies the technical process, saves the cost, realizes the goal of broadening the NOx conversion temperature window, and improves the sulfur resistance of the catalyst.